Leakage diagnosis apparatuses for diagnosing presence/absence of refrigerant leakage from refrigerant circuits have been known in the art. For example, Patent Document 1 describes an abnormality detection system as a leakage diagnosis apparatus of this type. The abnormality detection system is configured to detect refrigerant leakage using the degree of subcooling, the degree of superheat, the low-pressure and the high-pressure of the refrigeration cycle of the air conditioner apparatus, the outdoor temperature, the indoor temperature and the compressor rotational speed.
Patent Document 2 describes an analysis apparatus of a refrigeration apparatus for diagnosing failure of circuit components of a refrigerant circuit (e.g., the compressor) by analyzing the exergy of refrigerant in the circuit components.